The prior art ring laser gyroscope readout is described in U.S. Pat. No. 4,473,297, issued Sept. 25, 1984. Related patents include U.S. Pat. Nos. 4,257,015, issued Mar. 17, 1981, and 4,344,706, issued Aug. 17, 1982. The prior art ring laser gyroscope includes a triangular block having a triangular cavity, three mirrors disposed at respective corners of the cavity for reflecting a clockwise beam and a counterclockwise beam, one of said mirrors being a partly reflective type of mirror, and a readout assembly disposed at said partly reflective mirror, for measuring the gyroscope output.
One problem with the prior art ring laser gyroscope is that a defect in the readout subassembly causes an error in the readout reading and in the gyroscope output.